1. Technical Field
The present disclosure relates to optical pens and optical touch systems with the same.
2. Description of Related Art
An optical touch system includes an optical pen for projecting an infrared light spot onto an object and an infrared detector for capturing a track of the infrared light spot. The captured track of the infrared light spot can be processed and used for some applications, such as for inputting information.
The optical pen typically includes a housing, an infrared light source received in the housing for emitting infrared light, an optical lens configured for converging the light emitted from the light source and a pen tip positioned at an end of the housing for guiding the light out of the housing to project the infrared light onto an input area. In use, the light source emits light, and then the light passes through the optical lens and the pen tip and is projected onto the input area to form the infrared light spot. The detector is configured for detecting the track of the light spot. The optical lens generally includes an optical portion and a supporting portion around the optical portion. The optical portion is configured for converging light passing therethrough, and the supporting portion is configured for supporting the optical lens in the housing.
However, light emitted from the light source may enter into the supporting portion of the optical lens. When the light from the supporting portion is projected on the input area, undesired light spot may be formed on the input area. Therefore, the detecting accuracy of the detector may be reduced under the influence of the unwanted light spot, and even worse, the detector may misread the input information.
What is needed, therefore, is an optical pen and an optical touch system with the same to overcome the above-mentioned problems.